Tear-Strip for Paperboard Container

ABSTRACT

This invention relates to a paperboard container having a tearstrip, said tear-strip having its side edges each defined by a series of cuts, the terminal end of each cut being in advance of the initial end of the next following cut in the direction of tear of said tear-strip, the terminal end portion of each cut being inclined towards the next following cut.

Unite States Patent [191 [111 3,863,834 Sandford Feb. 4, 1975 TEAR-STRIP FOR PAPERBOARD 2,967,010 1/1961 Cuffey 229/51 TS CONTAINER 3,004,697 10/1961 Stone 229/51 TS Inventor: Peter E. Sandford, London, Ontario,

Canada Assignee: Somerville Industries Limited,

London, Ontario, Canada Filed: Oct. 9, 1973 Appl. No; 404,292

US. Cl. 229/51 TS Int. Cl B65d 5/54 Field of Search 229/51 TS, 51 SC References Cited UNITED STATES PATENTS Mai 229/51 TS Primary Examiner-Edward J. McCarthy Attorney, Agent, or Firm-Fetherstonhaugh & Co.

[57] ABSTRACT This invention relates to a paperboard container having a tear-strip, said tear-strip having its side edges each defined by a series of cuts, the terminal end of each cut being in advance of the initial end of the next following cut in the direction of tear of said tear-strip, the terminal end portion of each out being inclined towards the next following cut,

12 Claims, 4 Drawing Figures TEAR-STRIP FOR PAPERBOARD CONTAINER This invention relates to a tear-strip for a paperboard container and to a perforated line for a paperboard panel.

It is common practice to provide a tear-strip in a paperboard container. In use, the tear-strip is gripped at one end thereof and pulled to tear it from a panel of a container. In many cases, removal of the tear-strip permits the container to hinge open. In others, more than one tear-strip may be used to provide for removal of a portion of a container. This invention is not concerned with the application of a tear-strip, but rather with the construction of the tear-strip.

In the past, difficulty has been experienced in providing a tear-strip design that permits reliable and easy removal of the strip from its panel. In many cases, the free end of the strip that is gripped for removal breaks before the entire strip is torn from the panel. This invention provides an improved tear-strip construction which permits easier removal of the strip from the panel without breaking of the strip during the removal process.

Additionally, the invention provides a tear-strip that has resistance to folding along the perforated lines that form its side edges.

A paperboard container according to the present invention has a tear-strip, the side edges of which are each defined by a series of cuts. The terminal end of each cut is in advance of the initial end of the next following cut in the direction of tear of the tear-strip and the terminal end portion of each cut is inclined towards the initial end portion of the next following cut in each of said series of cuts.

The invention will be clearly understood after reference to the following detailed specification read in conjunction with the drawings.

In the drawings:

FIG. 1 is an illustration of a tray-type container having tear-strips in accordance with this invention;

FIG. 2 is a detailed illustration showing the manner in which a tear-strip according to this invention is made;

FIG. 3 is a view of a portion of a tear-strip according to this invention from the front after it has been torn from its panel; and

FIG. 4 is a view of a portion of a tear-strip shown in FIG. 3, but from the back.

Referring to the drawings, numeral refers to a paperboard container having tear-strips 12 in opposed side walls thereof. In the embodiment illustrated, the container is hardboard or chipboard. The container has a tray-like bottom portion 14 which contains articles and a cover top section 16. In use, the tear-strips 12 are removed to separate the cover portion 16 from the bottom 14 and leave the contained articles in the lower tray portion for display.

FIG. 1 is exemplary of using a tear-strip in a paperboard container. The invention, as indicated above, is concerned with the construction of the tear-strip and it is illustrated in detail in FIG. 2.

The tear-strip 18 is defined at each of its side edges by a series of through S-shaped cuts 20. The direction of tear is indicated by an arrow and the preferred direction of grain in the paperboard is indicated by an arrow. The tear-strip has a tab 22 at one end which is gripped by a user and pulled in an upward and forward direction to remove the tear-strip 18 from the panel.

It will be noted that in the tear-strip illustrated, the terminal end 24 of each cut 20 in the series is in advance of the initial end 26 of the next following cut in the direction of tear. It will also be noted that the terminal end portion of each cut is inclined to the direction of tear and towards the next following cut. The terminal end portion of each cut is substantially parallel to the terminal end portion of the next following cut.

In use and as the tear-strip is pulled from the panel, the cut portions readily separate. When the strip is pulled, pulling pressure is applied to the portion of the panel beyond the terminal end of each cut, and the panel is torn. In this connection, the terminal end portion of each cut slopes towards the next following cut so that tear of the panel is initiated in a direction towards the next following cut. At the same time, it will be noted that the initial portion of the next following cut to the one where tear is being initiated has been reached by the tear-strip in the direction of tear so that no tear force is required at the next following cut as the tear-strip is pulled and substantially all the force of the pull is applied to the tear initiation at the terminal end of the cut. The tear proceeds and is completed along an edge substantially like the edge 28 under normal conditions of tearing as the paperboard shears from back to front and the tear-strip when removed is left with a tab 30 that is thickest at its base and that diminishes in thickness from back to front towards its tip, as illustrated in FIGS. 3 and 4.

In the drawings, the grain direction of the hardboard is substantially at right angles to the direction of tear. Grain direction is essentially the direction of least resistance to tear and it will be noted from the free ends of the tabs 30 thatthe direction of the free edge of the tear of the panel is substantially aligned with thegrain direction of the hardboard. The pull tab will work with other grain directions. Grain direction is not critical to the operation of' the invention. For example, a panel having a tear-strip in which the grain direction of the hardboard is at right angles to that illustrated in the figures will work. A tear-strip with such a grain direction and cuts formed similarly to those illustrated in the drawings can be conveniently torn from the panel with the same effect, but the tear that is initiated from the terminal end of a cut extends from the terminal end of the cut in a direction substantially aligned with the grain direction. In such a case, the free edges of the torn tabs similar to the tabs 30 in the illustrations are substantially parallel with the longitudinal axis of the tear-strip. A grain direction between these two extremes is also possible. For example, a grain direction at 45 to the direction of the tear-strip is satisfactory. Here again, the direction of tear once initiated tends to extend from the terminal end of a cut in the direction of the grain to the next following cut. The free ends of the tabs similar to tabs 30 tend to be at an angle of about 45 to the direction of the tear-strip.

Thus, the direction of the grain of the paperboard is not critical provided that it is arranged that the tear once initiated extends towards and will communicate with the next following cut. The preferrred arrangement is the one illustrated.

A tear-strip according to the invention can be removed from a panel easily and without breaking.

There is another advantage to the tear-strip design herein described. It is that the series of cuts which define the edge portions of the tear-strip have considerable resistance to folding along the direction of the series of cuts because of theoverlapping S formation. This is of advantage in container construction where it is desired to have a fold line of a container closely spaced to the tear-strip. With the present invention, there is no tendency for the container to fold preferentially along a series of cuts rather than along the intended fold line of the container as the container is set up from the flat form. With some constructions for tear-strips of the prior art, there was a tendency for the container to fold preferentially along the series of cuts at the edge of the tear-strip rather than at the intended fold line of the container.

The series of cuts which define the side margins of the tear-strip can also be used to provide an especially useful weakened line that can be severed by running a thumbnail or the like along the line. This concept is useful in the making of a sealed package which can be opened by running a thumbnail around a perforated area that consists of a series of cuts similar to the series of cuts 20 that define each edge of the tear-strip. Such a cut of a general type is illustrated in U.S. Pat. No. 3,727,828 to Hall. There has been a difficulty with perforated lines of this type in that they lack strength if they are made with cuts sufficiently close to permit ready opening. They tend to break open when heavy articles are packaged therein.

The'herein disclosed interlocking S-type curve for a cut line has substantially more strength than previous cut lines when used as a perforated line for a sealed package. At the same time, it breaks easily when subjected to breaking pressure by thumb. It is, therefore, intended that the series of cuts which form the marginal portions of the herein disclosed tear-strip can be used as a weakened perforated line in the making of a sealed container that can be manually broken to open the container.

The embodiment of the invention illustrated shows a tear-strip in hardboard often called chipboard. It is, however, intended that the invention should apply to paperboards other than hardboard such as corrugated board.

Embodiments of the invention other than the one illustrated will be apparent to those skilled in the art. An important feature of the invention is the provision of a tear-strip defined by perforated lines that have a series of cuts having their terminal end in advance of the initial end of the next following cut and their terminal end portions inclining in a direction towards the next following cut. This arrangement provides for an easy tear initiation.

What I claim as my invention is:

l. A paperboard container having a tear-strip in a panel thereof, said tear-strip having its side edges each defined by a series of cuts,

the terminal end of each cut being in advance of the initial end of the next following cut in the direction of tear of said tear-strip,

the terminal end portion of each cut being inclined in a direction that intersects the next following cut a substantial distance from its initial end whereby pulling force on the strip in the direction of tear is applied substantially to tear initiation at the terminal ends of said cuts in succession.

2. A paperboard container having a tear-strip as claimed in claim 1 in which the terminal end portion of each cut is in substantially parallel spaced relation to the initial end portion of the next following cut.

3. A paperboard container having a tear-strip as claimed in claim 2 in which said cuts are S-shaped.

4. A paperboard panel having a perforated line,

said perforated line comprising:

a series of cuts in said panel, the terminal end of each cut being in advance of the initial end of the next following cut in the direction of progression of said series,

the terminal end portion of each cut being inclined in a direction that intersects the next following cut a substantial distance from its initial end whereby seperating force along said line in the direction of progression of said series of cuts is applied substantially to tear initiation at the terminal ends of said cuts in succession.

5. A paperboard panel having a perforated line as claimed in claim 4 in which the terminal end portion of each cut is in substantially parallel spaced relation to the initial end portion of the next following cut.

6. A paperboard panel having a perforated line as claimed in claim 5 in which said cuts are S-shaped.

7. A paperboard container having a tear-strip as claimed in claim 1 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.

8. A paperboard container having a tear-strip as claimed in claim 2 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.

9. A paperboard container having a tear-stripas claimed in claim 3 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.

10. A paperboard panel having a perforated line as claimed in claim 4 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.

11. A paperboard panel having a perforated line as claimed in claim 5 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.

12. A paperboard panel having a perforated line as claimed in claim 6 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut. 

1. A paperboard container having a tear-strip in a panel thereof, said tear-strip having its side edges each defined by a series of cuts, the terminal end of each cut being in advance of the initial end of the next following cut in the direction of tear of said tear-strip, the terminal end portion of each cut being inclined in a direction that intersects the next following cut a substantial distance from its initial end whereby pulling force on the strip in the direction of tear is applied substantially to tear initiation at the terminal ends of said cuts in succession.
 2. A paperboard container having a tear-strip as claimed in claim 1 in which the terminal end portion of each cut is in substantially parallel spaced relation to the initial end portion of the next following cut.
 3. A paperboard container having a tear-strip as claimed in claim 2 in which said cuts are S-shaped.
 4. A paperboard panel having a perforated line, said perforated line comprising: a series of cuts in said panel, the terminal end of each cut being in advance of the initial end of the next following cut in the direction of progression of said series, the terminal end portion of each cut being inclined in a direction that intersects the next following cut a substantial distance from its initial end whereby seperating force along said line in the direction of progression of said series of cuts is applied substantially to tear initiation at the terminal ends of said cuts in suceEssion.
 5. A paperboard panel having a perforated line as claimed in claim 4 in which the terminal end portion of each cut is in substantially parallel spaced relation to the initial end portion of the next following cut.
 6. A paperboard panel having a perforated line as claimed in claim 5 in which said cuts are S-shaped.
 7. A paperboard container having a tear-strip as claimed in claim 1 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.
 8. A paperboard container having a tear-strip as claimed in claim 2 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.
 9. A paperboard container having a tear-strip as claimed in claim 3 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.
 10. A paperboard panel having a perforated line as claimed in claim 4 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.
 11. A paperboard panel having a perforated line as claimed in claim 5 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut.
 12. A paperboard panel having a perforated line as claimed in claim 6 in which a line starting from the terminal end of each cut and proceeding in the direction of grain of the paperboard intersects the next following cut. 